/*
 * @(#)BeanContextServices.java	1.6 00/02/02
 *
 * Copyright 1998-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package java.beans.beancontext;

import java.util.Iterator;

import java.util.TooManyListenersException;

import java.beans.beancontext.BeanContext;

import java.beans.beancontext.BeanContextServiceProvider;

import java.beans.beancontext.BeanContextServicesListener;


/**
 * <p>
 * The BeanContextServices interface provides a mechanism for a BeanContext
 * to expose generic "services" to the BeanContextChild objects within.
 * </p>
 */
public interface BeanContextServices extends BeanContext, BeanContextServicesListener {

    /**
     * Adds a service to this BeanContext.
     * <code>BeanContextServiceProvider</code>s call this method 
     * to register a particular service with this context. 
     * If the service has not previously been added, the 
     * <code>BeanContextServices</code> associates
     * the service with the <code>BeanContextServiceProvider</code> and 
     * fires a <code>BeanContextServiceAvailableEvent</code> to all 
     * currently registered <code>BeanContextServicesListeners</code>. 
     * The method then returns <code>true</code>, indicating that 
     * the addition of the service was successful.
     * If the given service has already been added, this method 
     * simply returns <code>false</code>.
     * @param <code>serviceClass</code> the service to add
     * @param serviceProvider the <code>BeanContextServiceProvider</code> 
     * associated with the service
     */
    boolean addService(Class serviceClass, BeanContextServiceProvider serviceProvider);

    /**
     * BeanContextServiceProviders wishing to remove 
     * a currently registered service from this context
     * may do so via invocation of this method. Upon revocation of 
     * the service, the <code>BeanContextServices</code> fires a 
     * <code>BeanContextServiceRevokedEvent</code> to its
     * list of currently registered 
     * <code>BeanContextServiceRevokedListeners</code> and 
     * <code>BeanContextServicesListeners</code>.
     * @param serviceClass the service to revoke from this BeanContextServices
     * @param serviceProvider the BeanContextServiceProvider associated with
     * this particular service that is being revoked
     * @param revokeCurrentServicesNow a value of <code>true</code> 
     * indicates an exceptional circumstance where the 
     * <code>BeanContextServiceProvider</code> or
     * <code>BeanContextServices</code> wishes to immediately 
     * terminate service to all currently outstanding references 
     * to the specified service.
     */
    void revokeService(Class serviceClass, BeanContextServiceProvider serviceProvider, boolean revokeCurrentServicesNow);

    /**
     * Reports whether or not a given service is 
     * currently available from this context.
     * @param serviceClass the service in question
     * @return true if the service is available
     */
    boolean hasService(Class serviceClass);

    /**
     * A <code>BeanContextChild</code>, or any arbitrary object 
     * associated with a <code>BeanContextChild</code>, may obtain 
     * a reference to a currently registered service from its 
     * nesting <code>BeanContextServices</code> 
     * via invocation of this method. When invoked, this method
     * gets the service by calling the getService() method on the 
     * underlying <code>BeanContextServiceProvider</code>.
     * @param child the <code>BeanContextChild</code> 
     * associated with this request
     * @param requestor the object requesting the service
     * @param serviceClass class of the requested service
     * @param serviceSelector the service dependent parameter
     * @param bcsrl the 
     * <code>BeanContextServiceRevokedListener</code> to notify
     * if the service should later become revoked
     * @throws TooManyListenersException 
     * @return a reference to this context's named 
     * Service as requested or <code>null</code>
     */
    Object getService(BeanContextChild child, Object requestor, Class serviceClass, Object serviceSelector, BeanContextServiceRevokedListener bcsrl) throws TooManyListenersException;

    /**
     * Releases a <code>BeanContextChild</code>'s 
     * (or any arbitrary object associated with a BeanContextChild) 
     * reference to the specified service by calling releaseService() 
     * on the underlying <code>BeanContextServiceProvider</code>.
     * @param child the <code>BeanContextChild</code>
     * @param requestor the requestor
     * @param service the service
     */
    void releaseService(BeanContextChild child, Object requestor, Object service); 

    /**
     * Gets the currently available services for this context.
     * @return an <code>Iterator</code> consisting of the 
     * currently available services
     */
    Iterator getCurrentServiceClasses();

    /**
     * Gets the list of service dependent service parameters 
     * (Service Selectors) for the specified service, by 
     * calling getCurrentServiceSelectors() on the
     * underlying BeanContextServiceProvider.
     * @param serviceClass the specified service
     * @return the currently available service selectors 
     * for the named serviceClass
     */
    Iterator getCurrentServiceSelectors(Class serviceClass);

    /**
     * Adds a <code>BeanContextServicesListener</code> to this BeanContext
     * @param bcsl the <code>BeanContextServicesListener</code> to add
     */
    void addBeanContextServicesListener(BeanContextServicesListener bcsl);

    /**
     * Removes a <code>BeanContextServicesListener</code> 
     * from this <code>BeanContext</code>
     * @param bcsl the <code>BeanContextServicesListener</code> 
     * to remove from this context
     */
    void removeBeanContextServicesListener(BeanContextServicesListener bcsl);
}